I have spent the last few months researching the correct wiper blades/housing for my truck. It appears the vast majority of what is out there is JUNK. I went through about 8 sets from newer style to correct period aftermarket stuff before finding something that would actually stay on. Here is the only thing I found to work but make sure they send the 7mm to 5 mm flat adapter with it.
http://www.ebay.com/itm/121188538529...84.m1497.l2649
Below is a picture of one of the many aftermarkets I received. This one came from Tim Tygarts Obsolete Chevy parts. After sending them back I was told that their R&D team saw nothing wrong with it??? The hole is twice the size as the wiper arm end and the blades would come off with a flip of the finger or a slight twist. This is the third time (out of 5) I have sent something back to them that was an obvious quality issue and the response was "we have never had a complaint" or "we see nothing wrong with the product". They claim the product came form The Truck Shop but I don't have any info on that.